Wheel Loader Komatsu WA320-5 WA320-6 Hydraulic Pump Piston Pump Main Hydraulic Pump 419-18-31102 419-18-31101 Common Faults Insufficient pump output flow, slow loader movements Low system pressure, weak lifting performance Abnormal noise from hydraulic pump with vibration Oil leakage on pump housing, damaged seals Internal pump wear and overheating Severe pressure fluctuation and jerky operation Purchasing Recommendations Verify machine serial number and hydraulic pump part